How to Safely Install Underground Electrical Lines for Outdoor Lighting

Installing underground electrical lines for outdoor lighting can seem daunting, but with proper planning and safety precautions, it can be done safely by a homeowner. Here is a step-by-step guide to help you successfully install underground electrical lines to power outdoor lighting fixtures.

Researching Electrical Code Requirements

The first step is to research your local electrical code requirements. Electrical codes provide important safety guidelines and determine how deep your electrical lines must be buried.

Key things to research in your local electrical code:

Thorough research of the code requirements will ensure your installation meets all safety standards. I researched my local electrical code and determined a 12 inch burial depth and PVC conduit was required.

Planning the Electrical Layout

Next, plan the layout of the underground electrical lines.

Important factors to consider for your layout:

I sketched a rough layout showing the house power source, the 10 yard lights I was installing around my deck, and the routes for the underground lines. Planning it out on paper first made it easier to visualize the full scope of the project.

Gathering the Right Materials

There are several key materials needed to complete the installation:

I made a complete list of all materials and hardware I would need based on my plan. Having everything ready ahead of time ensured I could efficiently install the electrical system.

Digging the Trenches

Now it's time to start digging. Outline the paths for your planned buried lines and use a trenching shovel or excavator to dig trenches 12-18 inches deep.

Key tips for digging trenches safely:

I called 811, then used a rental excavator to dig my trenches 12 inches deep along the paths I had outlined. I made sure to call in advance and schedule my equipment rental.

Installing the Conduit

The conduit piping encases and protects the electrical wiring underground.

To install conduit properly:

I used PVC cement to glue all the conduit connections securely. This creates a continuous enclosed path for pulling the wires.

Running the Wiring Through the Conduit

Now you're ready to run the outdoor-rated electrical wires through the conduit.

Helpful tips for wiring:

I used a fish tape to easily pull the wiring through the entire underground conduit system. Leaving slack at the endpoints gave me plenty of room to work.

Connecting the Wiring to Fixtures and Power Source

The final step is to connect the buried wiring to your lighting fixtures, power source, and any switches or control boxes.

I connected my lighting fixtures to the emerge wires using silicone wire nuts. I used an outdoor GFCI outlet with an in-use cover to connect the power source from my house.

Closing Up and Finishing Touches

Once all electrical connections are made and tested, you can close up the trenches and complete the finished look.

After backfilling the trenches, I stapled the conduit piping to secure it and provide protection. Then I tested all the lighting fixtures and dimmer controls. My underground lighting installation was complete!

Installing underground electrical lines is manageable if local codes are followed using proper materials and safety precautions. Proper planning of the layout and wiring system is also key to a successful installation. With patience and attention to detail, you can have professional quality outdoor lighting powered by a concealed underground electrical system.